Light detectives – case study

Teacher Matt Boucher incorporated online citizen science projects Planet Hunters and Agent Exoplanet in a year 7/8 unit on light. Here, he reflects on what he and his students learned.

Inspiration for the unit

Our upcoming year 7/8 science unit on light contained a number of experiments and hands-on activities but was missing some of the ‘so what?’ I wanted to find a way to put our learning about light into a wider real-life context, allowing students to experience how scientists use light to make exciting discoveries.

Intended learning outcomes

I wanted students to learn about light and its properties as well as developing their scientific skills. Experiments already included in our unit developed the science capabilities ‘Gather and interpret data’ and ‘Use evidence’. I wanted to widen this to include ‘Interpret representations’, where students would be able to engage with data collected from light sources and see how scientists use the data for authentic purposes. I wanted students to explore more than what light does and begin to explore what light can tell us.

Teacher background

When planning for this unit in 2018, I had been a teacher for 14 years across a range of age levels. Science is a particular passion, and I am an amateur astronomer. I developed an Earth & Space Science programme and Astronomy Club when teaching at Kuranui College and brought my love of science to my role as Head of Science at South Wellington Intermediate School. In 2017, I participated in the Science Teaching Leadership Programme, and this helped me to focus on the science capabilities as a way of developing science for citizenship.

Class background

My students were a mixed year 7/8 class. They participated in specialist science classes twice per week for 1.5 hours each session. This means year 8 students have had an additional year of experience with science compared to year 7 students. All students had been introduced to the science capabilities and were used to discussing the skills that they had developed and practised in science lessons.

What happened

• Students learned about light and its behaviours through a series of investigations (see the unit plan).
• I introduced the concept of exoplanets (planets that orbit stars other than our Sun), including how new this field is and what kinds of discoveries have been made.
• I modelled the collection of light brightness data from telescopes by setting up a telescope off focus and pointed at a lamp. I spun a tennis ball around so that it obscured the light and demonstrated the dimming of the light from a star as a planet passes in front of it.

• I created another model of an exoplanet passing in front of its star by blacking out a room and making a large orange exercise ball glow. I passed a ball in front of the ‘star’ and had students use a light meter app to take brightness readings. They then graphed the data.
• When using both of these models, I demonstrated and we discussed how different distances of orbits and sizes of planets would affect our readings.
• Students spent one session using the online citizen science (OCS) project Agent Exoplanet, which taught them how readings are taken from telescope data and analysed to form a graph.
• Students spent one session using the OCS project Planet Hunters, which allowed them to view a series of graphs and use their knowledge to interpret which graphs showed a transiting exoplanet.
• Finally, students researched some of the exoplanets that have been found by the transit method and created a poster showing their properties having learned how these properties were discovered.

What worked well

This was the first time I incorporated the mini-unit of exoplanet discovery into a unit on light. The OCS projects I used focused on the processing of telescope photo data to form graphs and the interpretation of graphs to determine if a planet is present around a star. Students did not collect the data themselves – this would be impossible in school, so accessing existing data was a huge advantage. It also gave my students opportunities to work in-depth with the science capability ‘Interpret representations’. Generally they must either painstakingly create graphs through their own work gathering data and recording it or they are subjected to graphs that they do not understand since they do not understand all of the processes that went into creating it.

To help students understand what the data means, I used several models to show how the data would have been collected. I then sequenced the use of the two projects to build on this knowledge. Agent Exoplanet enables students to set parameters by which a graph would be generated. Planet Hunters provided graphs for the students to interpret.

Overall, the mini-unit made the wider light unit more interesting, engaging, memorable and effective.

Student learning

The mini-unit on exoplanets, including the two online citizen science projects, supported students’ learning about the physics of light (light travels in a straight line, the nature of shadows and the amplitude of light).

It also developed students’ science capability ‘Interpret representations’ as they explored how graphs are created and then interpreted.

Formative evidence of this learning included discussions with students and watching them work. Summative evidence included student-created posters exploring exoplanets and showing understanding of their different features.

Reflecting on using an online citizen science tool

Use of online citizen science (OCS) tools helped to expand the scope of my unit – astronomically!

This is a great way to expand beyond the bounds of the classroom and to engage in real science, in this case without actually leaving the classroom.

Matt Boucher

The two OCS projects I used only focused on interpreting data, so it was necessary to model the data collection so that students could understand what they were engaging in. I think this scaffolding will be necessary for all OCS projects.

Having more than one OCS project was also great, as the tasks were related but slightly different, allowing students to engage in different ways.

The challenges

The main challenge, besides variable wifi connectivity, was maintaining the focus and interest of all the students over a period of time. Some students were enraptured and engaged throughout even tedious repetitive tasks. Others lost focus more quickly. Having two different OCS projects related to our learning allowed students who began to lose focus with one to switch to the other, keeping them engaged in working scientifically.

Researcher’s comment

The way Matt used physical models in his classroom to demonstrate the process astronomers use in identifying exoplanets made this learning accessible and understandable for students. This was a strength of his unit – students were clear about what the graphs meant.

Agent Exoplanet provided opportunities for students to identify blank sky and the relative brightness of stars. As citizen scientists add calibration markers (stars of similar size and brightness), the accuracy of the light intensity graph increases. Engaging in this process enabled students to learn about ways that scientists replicate, adjust and check measurements for consistency, therefore providing more accurate data.