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 …

weather station

visitors this year: 28 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...

burning a candle

visitors this year: 65 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...

reaction rate: thiosulfate & acid

visitors this year: 345 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...

battery life

visitors this year: 24 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...

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.

types of battery

visitors this year: 57 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...

photosynthesis

visitors this year: 218 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...

when do plants grow

visitors this year: 61 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...

changes in an aquarium

visitors this year: 156 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...

investigating the enzyme amylase

visitors this year: 76 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...

checking a TV remote controller

visitors this year: 76 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...

rates of reaction

visitors this year: 300 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...

light sensor & colorimeter

visitors this year: 98 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...