Tagged: light sensor

primary: which colour for cycling

Most substances reflect some light and that is why we can see them. White light is a mixture of many colours mixed together. When white light shines on say, a blue fabric, the fabric reflects blue and absorbs every colour except blue. Similarly a red fabric reflects red and absorbs all other colours. A black fabric …

primary: which light is brightest?

We need light to see things and light comes from something that is hot or burning. A torch or light bulb has tungsten wire which glows when hot. Candles produce light by burning chemicals. Some light ..

weather station

Weather station With a data logger several sensors can be used together to monitor the weather over periods lasting weeks. Suitable sensors include temperature, pressure, humidity, light or even a rotation sensor to check...

burning a candle

Burning a candle As a candle burns oxygen is used and heat and water are produced. A few sensors can be used to monitor this process – including a light sensor to indicate when...

reaction rate: thiosulfate & acid

Rates: Thiosulfate and acid Sodium thiosulfate and acid react to form a precipitate. The light sensor can be used, like a colorimeter, to monitor the rate of the reaction. In this experiment we study...

battery life

Battery life In this experiment an electrical cell is tested to exhaustion. The cell might be a dry-cell, an alkaline cell or a lead-acid accumulator. The decreasing voltage is measured over a (long) period...

enzymes: starch & amylase; pepsin & protein

Two experiments: in one amylase catalyses the hydrolysis of starch. Iodine can be used as an indicator to show that the starch has been broken down. A light sensor can be used, like a colorimeter, to monitor this change.
Another experiment aims to show the effect of different temperatures on the action of amylase.This experiment studies
the effect of the enzyme pepsin on protein. Pepsin catalyses the hydrolysis of the protein, albumin into amino acids. As the protein solution is cloudy and amino acids are soluble the liquid changes from cloudy to clear. The light sensor can be used, like a colorimeter, to monitor this change.

a data logger is a scientist’s camera

data loggers – the scientist’s camera! There is a rich world of data waiting to be collected. Take an accelerometer with you on a theme park roller coaster or if that’s too sad, take...

types of battery

Batteries are a handy source of power. You’ll know that there are different kinds of batteries, and maybe that some are good for some jobs, and some for others. But battery power is expensive. It...

photosynthesis

How are plants affected by light? During photosynthesis oxygen is produced. How much photosynthesis occurs depends on how much light there is. You can measure the amount of oxygen produced using sensors connected to...

when do plants grow

It’s not easy to measure how fast a plant grows. You would probably not be too keen to take measurements every few hours – and especially not overnight. There are ways, however, of seeing...

changes in an aquarium

Life in any aquatic habitat has to be supported by oxygen. We are all too familiar with rivers and streams where the oxygen supply has been exhausted and the river dies. The production and...

investigating the enzyme amylase

Amylase catalyses the breakdown of starch into sugar. How is the activity of this enzyme affected by temperature? You can start to find out by monitoring the activity at different temperatures. You use Iodine...

measuring visible change in liquids

Measuring the appearance of cloudy sulfur when we mix acid and sodium thiosulfate is a popular science teaching activity. We can change the temperature or concentration of the reagents, and see whether the mixture...

day and night light & temperature

What time does it get light in the morning? When does it get dark? Is the central heating working? I just had to know, so I took my data logging equipment and started to...

checking a TV remote controller

An infrared remote control unit sends messages, using infrared ‘light’ to recorders and televisions. Point a remote controller at a light sensor and it may be able to pick up the signal. This likely works...

colorimeter for acid reacting with thiosulfate

A colorimeter for the reaction of acid and thiosulfate – rates of reaction The reaction of acid with thiosulfate produces a precipitate in a beaker, and we normally measured how quickly a cross drawn...

rates of reaction

what affects the rate of reaction? A chemical reaction can be made to go fast or slow. In this activity you will try to measure how a chemical reaction is affected by temperature. When...

light sensor & colorimeter

Often used elaborately to produce a makeshift colorimeter, the light is very useful for many biology and chemistry experiments on rates of reactions. As monochromatic light is less important with turbid solutions the makeshift...